AN4159

Software

Doc ID 023639 Rev 3

17/27

General presentation of the concept

A linear pressure temperature compensation is implemented in the ASIC, using 3

embedded sensor calibration point information.

A second order of accuracy can be achieved (less pressure variation when temperature

changes) by implementing a quadratic compensation (second order polynomial

approximation) on top of the piecewise linear (PWL) one, by S/W, using the same calibration

data built-in the sensor registers.

Here we describe the basic quadratic concept, assuming the T0 = 10 °C:

Figure 7.

Overview first to second order compensation

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Input parameters: TCV1, TCV2, TCS1, TCS2, Dgain

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Constants parameter: T1=480*(10-42.5)LSB; T2=0 LSB, T3=480*(70-42.5) LSB;

P0=1000mbar.

Step 1: pressure calibration points calculation

Equation 1